[net-next-2.6.git] / net / ipv4 / netfilter / nf_conntrack_l3proto_ipv4.c

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *	- move L3 protocol dependent part to this file.
 * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *	- add get_features() to support various size of conntrack
 *	  structures.
 *
 * Derived from net/ipv4/netfilter/ip_conntrack_standalone.c
 */

#include <linux/types.h>
#include <linux/ip.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmp.h>
#include <linux/sysctl.h>
#include <net/route.h>
#include <net/ip.h>

#include <linux/netfilter_ipv4.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_protocol.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(format, args...)
#endif

DECLARE_PER_CPU(struct nf_conntrack_stat, nf_conntrack_stat);

static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
			     struct nf_conntrack_tuple *tuple)
{
	u_int32_t _addrs[2], *ap;
	ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
				sizeof(u_int32_t) * 2, _addrs);
	if (ap == NULL)
		return 0;

	tuple->src.u3.ip = ap[0];
	tuple->dst.u3.ip = ap[1];

	return 1;
}

static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
			   const struct nf_conntrack_tuple *orig)
{
	tuple->src.u3.ip = orig->dst.u3.ip;
	tuple->dst.u3.ip = orig->src.u3.ip;

	return 1;
}

static int ipv4_print_tuple(struct seq_file *s,
			    const struct nf_conntrack_tuple *tuple)
{
	return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
		          NIPQUAD(tuple->src.u3.ip),
			  NIPQUAD(tuple->dst.u3.ip));
}

static int ipv4_print_conntrack(struct seq_file *s,
				const struct nf_conn *conntrack)
{
	return 0;
}

/* Returns new sk_buff, or NULL */
static struct sk_buff *
nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
{
	skb_orphan(skb);

        local_bh_disable();
        skb = ip_defrag(skb, user);
        local_bh_enable();

        if (skb)
		ip_send_check(skb->nh.iph);

        return skb;
}

static int
ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
	     u_int8_t *protonum)
{
	/* Never happen */
	if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) {
		if (net_ratelimit()) {
			printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
			(*pskb)->nh.iph->protocol, hooknum);
		}
		return -NF_DROP;
	}

	*dataoff = (*pskb)->nh.raw - (*pskb)->data + (*pskb)->nh.iph->ihl*4;
	*protonum = (*pskb)->nh.iph->protocol;

	return NF_ACCEPT;
}

int nat_module_is_loaded = 0;
static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple)
{
	if (nat_module_is_loaded)
		return NF_CT_F_NAT;

	return NF_CT_F_BASIC;
}

static unsigned int ipv4_confirm(unsigned int hooknum,
				 struct sk_buff **pskb,
				 const struct net_device *in,
				 const struct net_device *out,
				 int (*okfn)(struct sk_buff *))
{
	/* We've seen it coming out the other side: confirm it */
	return nf_conntrack_confirm(pskb);
}

static unsigned int ipv4_conntrack_help(unsigned int hooknum,
				      struct sk_buff **pskb,
				      const struct net_device *in,
				      const struct net_device *out,
				      int (*okfn)(struct sk_buff *))
{
	struct nf_conn *ct;
	enum ip_conntrack_info ctinfo;
	struct nf_conn_help *help;

	/* This is where we call the helper: as the packet goes out. */
	ct = nf_ct_get(*pskb, &ctinfo);
	if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
		return NF_ACCEPT;

	help = nfct_help(ct);
	if (!help || !help->helper)
		return NF_ACCEPT;

	return help->helper->help(pskb,
			       (*pskb)->nh.raw - (*pskb)->data
					       + (*pskb)->nh.iph->ihl*4,
			       ct, ctinfo);
}

static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
					  struct sk_buff **pskb,
					  const struct net_device *in,
					  const struct net_device *out,
					  int (*okfn)(struct sk_buff *))
{
#if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE)
	/* Previously seen (loopback)?  Ignore.  Do this before
	   fragment check. */
	if ((*pskb)->nfct)
		return NF_ACCEPT;
#endif

	/* Gather fragments. */
	if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) {
		*pskb = nf_ct_ipv4_gather_frags(*pskb,
						hooknum == NF_IP_PRE_ROUTING ?
						IP_DEFRAG_CONNTRACK_IN :
						IP_DEFRAG_CONNTRACK_OUT);
		if (!*pskb)
			return NF_STOLEN;
	}
	return NF_ACCEPT;
}

static unsigned int ipv4_conntrack_in(unsigned int hooknum,
				      struct sk_buff **pskb,
				      const struct net_device *in,
				      const struct net_device *out,
				      int (*okfn)(struct sk_buff *))
{
	return nf_conntrack_in(PF_INET, hooknum, pskb);
}

static unsigned int ipv4_conntrack_local(unsigned int hooknum,
				         struct sk_buff **pskb,
				         const struct net_device *in,
				         const struct net_device *out,
				         int (*okfn)(struct sk_buff *))
{
	/* root is playing with raw sockets. */
	if ((*pskb)->len < sizeof(struct iphdr)
	    || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) {
		if (net_ratelimit())
			printk("ipt_hook: happy cracking.\n");
		return NF_ACCEPT;
	}
	return nf_conntrack_in(PF_INET, hooknum, pskb);
}

/* Connection tracking may drop packets, but never alters them, so
   make it the first hook. */
static struct nf_hook_ops ipv4_conntrack_ops[] = {
	{
		.hook		= ipv4_conntrack_defrag,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_PRE_ROUTING,
		.priority	= NF_IP_PRI_CONNTRACK_DEFRAG,
	},
	{
		.hook		= ipv4_conntrack_in,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_PRE_ROUTING,
		.priority	= NF_IP_PRI_CONNTRACK,
	},
	{
		.hook           = ipv4_conntrack_defrag,
		.owner          = THIS_MODULE,
		.pf             = PF_INET,
		.hooknum        = NF_IP_LOCAL_OUT,
		.priority       = NF_IP_PRI_CONNTRACK_DEFRAG,
	},
	{
		.hook		= ipv4_conntrack_local,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_LOCAL_OUT,
		.priority	= NF_IP_PRI_CONNTRACK,
	},
	{
		.hook		= ipv4_conntrack_help,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_POST_ROUTING,
		.priority	= NF_IP_PRI_CONNTRACK_HELPER,
	},
	{
		.hook		= ipv4_conntrack_help,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_LOCAL_IN,
		.priority	= NF_IP_PRI_CONNTRACK_HELPER,
	},
	{
		.hook		= ipv4_confirm,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_POST_ROUTING,
		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM,
	},
	{
		.hook		= ipv4_confirm,
		.owner		= THIS_MODULE,
		.pf		= PF_INET,
		.hooknum	= NF_IP_LOCAL_IN,
		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM,
	},
};

#ifdef CONFIG_SYSCTL
/* From nf_conntrack_proto_icmp.c */
extern unsigned int nf_ct_icmp_timeout;
static struct ctl_table_header *nf_ct_ipv4_sysctl_header;

static ctl_table nf_ct_sysctl_table[] = {
	{
		.ctl_name	= NET_NF_CONNTRACK_ICMP_TIMEOUT,
		.procname	= "nf_conntrack_icmp_timeout",
		.data		= &nf_ct_icmp_timeout,
		.maxlen		= sizeof(unsigned int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
	},
        { .ctl_name = 0 }
};

static ctl_table nf_ct_netfilter_table[] = {
	{
		.ctl_name       = NET_NETFILTER,
		.procname       = "netfilter",
		.mode           = 0555,
		.child          = nf_ct_sysctl_table,
	},
	{ .ctl_name = 0 }
};

static ctl_table nf_ct_net_table[] = {
	{
		.ctl_name       = CTL_NET,
		.procname       = "net",
		.mode           = 0555,
		.child          = nf_ct_netfilter_table,
	},
	{ .ctl_name = 0 }
};
#endif

/* Fast function for those who don't want to parse /proc (and I don't
   blame them). */
/* Reversing the socket's dst/src point of view gives us the reply
   mapping. */
static int
getorigdst(struct sock *sk, int optval, void __user *user, int *len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct nf_conntrack_tuple_hash *h;
	struct nf_conntrack_tuple tuple;
	
	NF_CT_TUPLE_U_BLANK(&tuple);
	tuple.src.u3.ip = inet->rcv_saddr;
	tuple.src.u.tcp.port = inet->sport;
	tuple.dst.u3.ip = inet->daddr;
	tuple.dst.u.tcp.port = inet->dport;
	tuple.src.l3num = PF_INET;
	tuple.dst.protonum = IPPROTO_TCP;

	/* We only do TCP at the moment: is there a better way? */
	if (strcmp(sk->sk_prot->name, "TCP")) {
		DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
		return -ENOPROTOOPT;
	}

	if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
		DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
		       *len, sizeof(struct sockaddr_in));
		return -EINVAL;
	}

	h = nf_conntrack_find_get(&tuple, NULL);
	if (h) {
		struct sockaddr_in sin;
		struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);

		sin.sin_family = AF_INET;
		sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
			.tuple.dst.u.tcp.port;
		sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
			.tuple.dst.u3.ip;
		memset(sin.sin_zero, 0, sizeof(sin.sin_zero));

		DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
		       NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
		nf_ct_put(ct);
		if (copy_to_user(user, &sin, sizeof(sin)) != 0)
			return -EFAULT;
		else
			return 0;
	}
	DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
	       NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
	       NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
	return -ENOENT;
}

#if defined(CONFIG_NF_CT_NETLINK) || \
    defined(CONFIG_NF_CT_NETLINK_MODULE)

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_conntrack.h>

static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
				const struct nf_conntrack_tuple *tuple)
{
	NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
		&tuple->src.u3.ip);
	NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
		&tuple->dst.u3.ip);
	return 0;

nfattr_failure:
	return -1;
}

static const size_t cta_min_ip[CTA_IP_MAX] = {
	[CTA_IP_V4_SRC-1]       = sizeof(u_int32_t),
	[CTA_IP_V4_DST-1]       = sizeof(u_int32_t),
};

static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
				struct nf_conntrack_tuple *t)
{
	if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1])
		return -EINVAL;

	if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
		return -EINVAL;

	t->src.u3.ip =
		*(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_SRC-1]);
	t->dst.u3.ip =
		*(u_int32_t *)NFA_DATA(tb[CTA_IP_V4_DST-1]);

	return 0;
}
#endif

static struct nf_sockopt_ops so_getorigdst = {
	.pf		= PF_INET,
	.get_optmin	= SO_ORIGINAL_DST,
	.get_optmax	= SO_ORIGINAL_DST+1,
	.get		= &getorigdst,
};

struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
	.l3proto	 = PF_INET,
	.name		 = "ipv4",
	.pkt_to_tuple	 = ipv4_pkt_to_tuple,
	.invert_tuple	 = ipv4_invert_tuple,
	.print_tuple	 = ipv4_print_tuple,
	.print_conntrack = ipv4_print_conntrack,
	.prepare	 = ipv4_prepare,
	.get_features	 = ipv4_get_features,
#if defined(CONFIG_NF_CT_NETLINK) || \
    defined(CONFIG_NF_CT_NETLINK_MODULE)
	.tuple_to_nfattr = ipv4_tuple_to_nfattr,
	.nfattr_to_tuple = ipv4_nfattr_to_tuple,
#endif
	.me		 = THIS_MODULE,
};

extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp4;
extern struct nf_conntrack_protocol nf_conntrack_protocol_udp4;
extern struct nf_conntrack_protocol nf_conntrack_protocol_icmp;

MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
MODULE_LICENSE("GPL");

static int __init nf_conntrack_l3proto_ipv4_init(void)
{
	int ret = 0;

	need_conntrack();

	ret = nf_register_sockopt(&so_getorigdst);
	if (ret < 0) {
		printk(KERN_ERR "Unable to register netfilter socket option\n");
		return ret;
	}

	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp4);
	if (ret < 0) {
		printk("nf_conntrack_ipv4: can't register tcp.\n");
		goto cleanup_sockopt;
	}

	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp4);
	if (ret < 0) {
		printk("nf_conntrack_ipv4: can't register udp.\n");
		goto cleanup_tcp;
	}

	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_icmp);
	if (ret < 0) {
		printk("nf_conntrack_ipv4: can't register icmp.\n");
		goto cleanup_udp;
	}

	ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
	if (ret < 0) {
		printk("nf_conntrack_ipv4: can't register ipv4\n");
		goto cleanup_icmp;
	}

	ret = nf_register_hooks(ipv4_conntrack_ops,
				ARRAY_SIZE(ipv4_conntrack_ops));
	if (ret < 0) {
		printk("nf_conntrack_ipv4: can't register hooks.\n");
		goto cleanup_ipv4;
	}
#ifdef CONFIG_SYSCTL
	nf_ct_ipv4_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
	if (nf_ct_ipv4_sysctl_header == NULL) {
		printk("nf_conntrack: can't register to sysctl.\n");
		ret = -ENOMEM;
		goto cleanup_hooks;
	}
#endif
	return ret;

#ifdef CONFIG_SYSCTL
 cleanup_hooks:
	nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
#endif
 cleanup_ipv4:
	nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
 cleanup_icmp:
	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
 cleanup_udp:
	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
 cleanup_tcp:
	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
 cleanup_sockopt:
	nf_unregister_sockopt(&so_getorigdst);
	return ret;
}

static void __exit nf_conntrack_l3proto_ipv4_fini(void)
{
	synchronize_net();
#ifdef CONFIG_SYSCTL
 	unregister_sysctl_table(nf_ct_ipv4_sysctl_header);
#endif
	nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
	nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
	nf_unregister_sockopt(&so_getorigdst);
}

module_init(nf_conntrack_l3proto_ipv4_init);
module_exit(nf_conntrack_l3proto_ipv4_fini);

EXPORT_SYMBOL(nf_ct_ipv4_gather_frags);
Commit	Line	Data
9fb9cbb1 YK	1	/* (C) 1999-2001 Paul `Rusty' Russell
	2	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
	9	* - move L3 protocol dependent part to this file.
	10	* 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
	11	* - add get_features() to support various size of conntrack
	12	* structures.
	13	*
	14	* Derived from net/ipv4/netfilter/ip_conntrack_standalone.c
	15	*/
	16
9fb9cbb1 YK	17	#include <linux/types.h>
	18	#include <linux/ip.h>
	19	#include <linux/netfilter.h>
	20	#include <linux/module.h>
	21	#include <linux/skbuff.h>
	22	#include <linux/icmp.h>
	23	#include <linux/sysctl.h>
0ae2cfe7	24	#include <net/route.h>
9fb9cbb1 YK	25	#include <net/ip.h>
	26
	27	#include <linux/netfilter_ipv4.h>
	28	#include <net/netfilter/nf_conntrack.h>
	29	#include <net/netfilter/nf_conntrack_helper.h>
	30	#include <net/netfilter/nf_conntrack_protocol.h>
	31	#include <net/netfilter/nf_conntrack_l3proto.h>
	32	#include <net/netfilter/nf_conntrack_core.h>
	33	#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
	34
	35	#if 0
	36	#define DEBUGP printk
	37	#else
	38	#define DEBUGP(format, args...)
	39	#endif
	40
	41	DECLARE_PER_CPU(struct nf_conntrack_stat, nf_conntrack_stat);
	42
	43	static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
	44	struct nf_conntrack_tuple *tuple)
	45	{
	46	u_int32_t _addrs[2], *ap;
	47	ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
	48	sizeof(u_int32_t) * 2, _addrs);
	49	if (ap == NULL)
	50	return 0;
	51
	52	tuple->src.u3.ip = ap[0];
	53	tuple->dst.u3.ip = ap[1];
	54
	55	return 1;
	56	}
	57
	58	static int ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
	59	const struct nf_conntrack_tuple *orig)
	60	{
	61	tuple->src.u3.ip = orig->dst.u3.ip;
	62	tuple->dst.u3.ip = orig->src.u3.ip;
	63
	64	return 1;
	65	}
	66
	67	static int ipv4_print_tuple(struct seq_file *s,
	68	const struct nf_conntrack_tuple *tuple)
	69	{
	70	return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ",
	71	NIPQUAD(tuple->src.u3.ip),
	72	NIPQUAD(tuple->dst.u3.ip));
	73	}
	74
	75	static int ipv4_print_conntrack(struct seq_file *s,
	76	const struct nf_conn *conntrack)
	77	{
	78	return 0;
	79	}
	80
	81	/* Returns new sk_buff, or NULL */
	82	static struct sk_buff *
	83	nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user)
	84	{
	85	skb_orphan(skb);
	86
	87	local_bh_disable();
	88	skb = ip_defrag(skb, user);
89	local_bh_enable();
90
91	if (skb)
92	ip_send_check(skb->nh.iph);
93
94	return skb;
95	}
96
97	static int
98	ipv4_prepare(struct sk_buff *pskb, unsigned int hooknum, unsigned int dataoff,
99	u_int8_t *protonum)
100	{
101	/* Never happen */
102	if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) {
103	if (net_ratelimit()) {
104	printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n",
105	(*pskb)->nh.iph->protocol, hooknum);
106	}
107	return -NF_DROP;
108	}
109
110	dataoff = (pskb)->nh.raw - (pskb)->data + (pskb)->nh.iph->ihl*4;
111	protonum = (pskb)->nh.iph->protocol;
112
113	return NF_ACCEPT;
114	}
115
116	int nat_module_is_loaded = 0;
117	static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple)
118	{
119	if (nat_module_is_loaded)
120	return NF_CT_F_NAT;
121
122	return NF_CT_F_BASIC;
123	}
124
125	static unsigned int ipv4_confirm(unsigned int hooknum,
126	struct sk_buff **pskb,
127	const struct net_device *in,
128	const struct net_device *out,
129	int (okfn)(struct sk_buff ))
130	{
131	/* We've seen it coming out the other side: confirm it */
132	return nf_conntrack_confirm(pskb);
133	}
134
135	static unsigned int ipv4_conntrack_help(unsigned int hooknum,
136	struct sk_buff **pskb,
137	const struct net_device *in,
138	const struct net_device *out,
139	int (okfn)(struct sk_buff ))
140	{
141	struct nf_conn *ct;
142	enum ip_conntrack_info ctinfo;
dc808fe2	143	struct nf_conn_help *help;
9fb9cbb1 YK	144
	145	/* This is where we call the helper: as the packet goes out. */
	146	ct = nf_ct_get(*pskb, &ctinfo);
6442f1cf	147	if (!ct \|\| ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY)
dc808fe2 HW	148	return NF_ACCEPT;
	149
	150	help = nfct_help(ct);
	151	if (!help \|\| !help->helper)
	152	return NF_ACCEPT;
	153
	154	return help->helper->help(pskb,
	155	(pskb)->nh.raw - (pskb)->data
	156	+ (pskb)->nh.iph->ihl4,
	157	ct, ctinfo);
9fb9cbb1 YK	158	}
	159
	160	static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
	161	struct sk_buff **pskb,
	162	const struct net_device *in,
	163	const struct net_device *out,
	164	int (okfn)(struct sk_buff ))
	165	{
	166	#if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE)
	167	/* Previously seen (loopback)? Ignore. Do this before
	168	fragment check. */
	169	if ((*pskb)->nfct)
	170	return NF_ACCEPT;
	171	#endif
	172
	173	/* Gather fragments. */
	174	if ((*pskb)->nh.iph->frag_off & htons(IP_MF\|IP_OFFSET)) {
	175	pskb = nf_ct_ipv4_gather_frags(pskb,
	176	hooknum == NF_IP_PRE_ROUTING ?
	177	IP_DEFRAG_CONNTRACK_IN :
	178	IP_DEFRAG_CONNTRACK_OUT);
	179	if (!*pskb)
	180	return NF_STOLEN;
	181	}
	182	return NF_ACCEPT;
	183	}
	184
9fb9cbb1 YK	185	static unsigned int ipv4_conntrack_in(unsigned int hooknum,
	186	struct sk_buff **pskb,
	187	const struct net_device *in,
	188	const struct net_device *out,
	189	int (okfn)(struct sk_buff ))
	190	{
	191	return nf_conntrack_in(PF_INET, hooknum, pskb);
	192	}
	193
	194	static unsigned int ipv4_conntrack_local(unsigned int hooknum,
	195	struct sk_buff **pskb,
	196	const struct net_device *in,
	197	const struct net_device *out,
	198	int (okfn)(struct sk_buff ))
	199	{
	200	/* root is playing with raw sockets. */
	201	if ((*pskb)->len < sizeof(struct iphdr)
	202	\|\| (pskb)->nh.iph->ihl 4 < sizeof(struct iphdr)) {
	203	if (net_ratelimit())
	204	printk("ipt_hook: happy cracking.\n");
	205	return NF_ACCEPT;
	206	}
	207	return nf_conntrack_in(PF_INET, hooknum, pskb);
	208	}
	209
	210	/* Connection tracking may drop packets, but never alters them, so
	211	make it the first hook. */
964ddaa1 PM	212	static struct nf_hook_ops ipv4_conntrack_ops[] = {
	213	{
	214	.hook = ipv4_conntrack_defrag,
	215	.owner = THIS_MODULE,
	216	.pf = PF_INET,
	217	.hooknum = NF_IP_PRE_ROUTING,
	218	.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
	219	},
	220	{
	221	.hook = ipv4_conntrack_in,
	222	.owner = THIS_MODULE,
	223	.pf = PF_INET,
	224	.hooknum = NF_IP_PRE_ROUTING,
	225	.priority = NF_IP_PRI_CONNTRACK,
	226	},
	227	{
	228	.hook = ipv4_conntrack_defrag,
	229	.owner = THIS_MODULE,
	230	.pf = PF_INET,
	231	.hooknum = NF_IP_LOCAL_OUT,
	232	.priority = NF_IP_PRI_CONNTRACK_DEFRAG,
	233	},
	234	{
	235	.hook = ipv4_conntrack_local,
	236	.owner = THIS_MODULE,
	237	.pf = PF_INET,
	238	.hooknum = NF_IP_LOCAL_OUT,
	239	.priority = NF_IP_PRI_CONNTRACK,
	240	},
	241	{
	242	.hook = ipv4_conntrack_help,
	243	.owner = THIS_MODULE,
	244	.pf = PF_INET,
	245	.hooknum = NF_IP_POST_ROUTING,
	246	.priority = NF_IP_PRI_CONNTRACK_HELPER,
	247	},
	248	{
	249	.hook = ipv4_conntrack_help,
	250	.owner = THIS_MODULE,
	251	.pf = PF_INET,
	252	.hooknum = NF_IP_LOCAL_IN,
	253	.priority = NF_IP_PRI_CONNTRACK_HELPER,
	254	},
	255	{
	256	.hook = ipv4_confirm,
	257	.owner = THIS_MODULE,
	258	.pf = PF_INET,
	259	.hooknum = NF_IP_POST_ROUTING,
	260	.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
	261	},
	262	{
	263	.hook = ipv4_confirm,
	264	.owner = THIS_MODULE,
	265	.pf = PF_INET,
	266	.hooknum = NF_IP_LOCAL_IN,
	267	.priority = NF_IP_PRI_CONNTRACK_CONFIRM,
	268	},
9fb9cbb1 YK	269	};
	270
	271	#ifdef CONFIG_SYSCTL
	272	/* From nf_conntrack_proto_icmp.c */
babbdb1a	273	extern unsigned int nf_ct_icmp_timeout;
9fb9cbb1 YK	274	static struct ctl_table_header *nf_ct_ipv4_sysctl_header;
	275
	276	static ctl_table nf_ct_sysctl_table[] = {
	277	{
	278	.ctl_name = NET_NF_CONNTRACK_ICMP_TIMEOUT,
	279	.procname = "nf_conntrack_icmp_timeout",
	280	.data = &nf_ct_icmp_timeout,
	281	.maxlen = sizeof(unsigned int),
	282	.mode = 0644,
	283	.proc_handler = &proc_dointvec_jiffies,
	284	},
	285	{ .ctl_name = 0 }
	286	};
	287
	288	static ctl_table nf_ct_netfilter_table[] = {
	289	{
	290	.ctl_name = NET_NETFILTER,
	291	.procname = "netfilter",
	292	.mode = 0555,
	293	.child = nf_ct_sysctl_table,
	294	},
	295	{ .ctl_name = 0 }
	296	};
	297
	298	static ctl_table nf_ct_net_table[] = {
	299	{
	300	.ctl_name = CTL_NET,
	301	.procname = "net",
	302	.mode = 0555,
	303	.child = nf_ct_netfilter_table,
	304	},
	305	{ .ctl_name = 0 }
	306	};
	307	#endif
	308
	309	/* Fast function for those who don't want to parse /proc (and I don't
	310	blame them). */
	311	/* Reversing the socket's dst/src point of view gives us the reply
	312	mapping. */
	313	static int
	314	getorigdst(struct sock sk, int optval, void __user user, int *len)
	315	{
	316	struct inet_sock *inet = inet_sk(sk);
	317	struct nf_conntrack_tuple_hash *h;
	318	struct nf_conntrack_tuple tuple;
	319
	320	NF_CT_TUPLE_U_BLANK(&tuple);
	321	tuple.src.u3.ip = inet->rcv_saddr;
	322	tuple.src.u.tcp.port = inet->sport;
	323	tuple.dst.u3.ip = inet->daddr;
	324	tuple.dst.u.tcp.port = inet->dport;
	325	tuple.src.l3num = PF_INET;
	326	tuple.dst.protonum = IPPROTO_TCP;
	327
	328	/* We only do TCP at the moment: is there a better way? */
	329	if (strcmp(sk->sk_prot->name, "TCP")) {
	330	DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n");
	331	return -ENOPROTOOPT;
	332	}
	333
	334	if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
	335	DEBUGP("SO_ORIGINAL_DST: len %u not %u\n",
	336	*len, sizeof(struct sockaddr_in));
	337	return -EINVAL;
338	}
339
340	h = nf_conntrack_find_get(&tuple, NULL);
341	if (h) {
342	struct sockaddr_in sin;
343	struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
344
345	sin.sin_family = AF_INET;
346	sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
347	.tuple.dst.u.tcp.port;
348	sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
349	.tuple.dst.u3.ip;
6c813c3f	350	memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
9fb9cbb1 YK	351
	352	DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n",
	353	NIPQUAD(sin.sin_addr.s_addr), ntohs(sin.sin_port));
	354	nf_ct_put(ct);
	355	if (copy_to_user(user, &sin, sizeof(sin)) != 0)
	356	return -EFAULT;
	357	else
	358	return 0;
	359	}
	360	DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n",
	361	NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port),
	362	NIPQUAD(tuple.dst.u3.ip), ntohs(tuple.dst.u.tcp.port));
	363	return -ENOENT;
	364	}
	365
c1d10adb PNA	366	#if defined(CONFIG_NF_CT_NETLINK) \|\| \
	367	defined(CONFIG_NF_CT_NETLINK_MODULE)
	368
	369	#include <linux/netfilter/nfnetlink.h>
	370	#include <linux/netfilter/nfnetlink_conntrack.h>
	371
	372	static int ipv4_tuple_to_nfattr(struct sk_buff *skb,
	373	const struct nf_conntrack_tuple *tuple)
	374	{
	375	NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t),
	376	&tuple->src.u3.ip);
	377	NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t),
	378	&tuple->dst.u3.ip);
	379	return 0;
	380
	381	nfattr_failure:
	382	return -1;
	383	}
	384
	385	static const size_t cta_min_ip[CTA_IP_MAX] = {
	386	[CTA_IP_V4_SRC-1] = sizeof(u_int32_t),
	387	[CTA_IP_V4_DST-1] = sizeof(u_int32_t),
	388	};
	389
	390	static int ipv4_nfattr_to_tuple(struct nfattr *tb[],
	391	struct nf_conntrack_tuple *t)
	392	{
	393	if (!tb[CTA_IP_V4_SRC-1] \|\| !tb[CTA_IP_V4_DST-1])
	394	return -EINVAL;
	395
	396	if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
	397	return -EINVAL;
	398
	399	t->src.u3.ip =
	400	(u_int32_t )NFA_DATA(tb[CTA_IP_V4_SRC-1]);
	401	t->dst.u3.ip =
	402	(u_int32_t )NFA_DATA(tb[CTA_IP_V4_DST-1]);
	403
	404	return 0;
	405	}
	406	#endif
	407
9fb9cbb1 YK	408	static struct nf_sockopt_ops so_getorigdst = {
	409	.pf = PF_INET,
	410	.get_optmin = SO_ORIGINAL_DST,
	411	.get_optmax = SO_ORIGINAL_DST+1,
	412	.get = &getorigdst,
	413	};
	414
	415	struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = {
	416	.l3proto = PF_INET,
	417	.name = "ipv4",
	418	.pkt_to_tuple = ipv4_pkt_to_tuple,
	419	.invert_tuple = ipv4_invert_tuple,
	420	.print_tuple = ipv4_print_tuple,
	421	.print_conntrack = ipv4_print_conntrack,
	422	.prepare = ipv4_prepare,
	423	.get_features = ipv4_get_features,
c1d10adb PNA	424	#if defined(CONFIG_NF_CT_NETLINK) \|\| \
	425	defined(CONFIG_NF_CT_NETLINK_MODULE)
	426	.tuple_to_nfattr = ipv4_tuple_to_nfattr,
	427	.nfattr_to_tuple = ipv4_nfattr_to_tuple,
	428	#endif
9fb9cbb1 YK	429	.me = THIS_MODULE,
	430	};
	431
	432	extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp4;
	433	extern struct nf_conntrack_protocol nf_conntrack_protocol_udp4;
	434	extern struct nf_conntrack_protocol nf_conntrack_protocol_icmp;
32292a7f PM	435
	436	MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
	437	MODULE_LICENSE("GPL");
	438
	439	static int __init nf_conntrack_l3proto_ipv4_init(void)
9fb9cbb1 YK	440	{
	441	int ret = 0;
	442
32292a7f	443	need_conntrack();
9fb9cbb1 YK	444
	445	ret = nf_register_sockopt(&so_getorigdst);
	446	if (ret < 0) {
	447	printk(KERN_ERR "Unable to register netfilter socket option\n");
32292a7f	448	return ret;
9fb9cbb1 YK	449	}
	450
	451	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp4);
	452	if (ret < 0) {
	453	printk("nf_conntrack_ipv4: can't register tcp.\n");
	454	goto cleanup_sockopt;
	455	}
	456
	457	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp4);
	458	if (ret < 0) {
	459	printk("nf_conntrack_ipv4: can't register udp.\n");
	460	goto cleanup_tcp;
	461	}
	462
	463	ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_icmp);
	464	if (ret < 0) {
	465	printk("nf_conntrack_ipv4: can't register icmp.\n");
	466	goto cleanup_udp;
	467	}
	468
	469	ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4);
	470	if (ret < 0) {
	471	printk("nf_conntrack_ipv4: can't register ipv4\n");
	472	goto cleanup_icmp;
	473	}
	474
964ddaa1 PM	475	ret = nf_register_hooks(ipv4_conntrack_ops,
964ddaa1 PM	476	ARRAY_SIZE(ipv4_conntrack_ops));
9fb9cbb1	477	if (ret < 0) {
964ddaa1	478	printk("nf_conntrack_ipv4: can't register hooks.\n");
9fb9cbb1 YK	479	goto cleanup_ipv4;
9fb9cbb1 YK	480	}
9fb9cbb1 YK	481	#ifdef CONFIG_SYSCTL
	482	nf_ct_ipv4_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
	483	if (nf_ct_ipv4_sysctl_header == NULL) {
	484	printk("nf_conntrack: can't register to sysctl.\n");
	485	ret = -ENOMEM;
964ddaa1	486	goto cleanup_hooks;
9fb9cbb1 YK	487	}
9fb9cbb1 YK	488	#endif
9fb9cbb1 YK	489	return ret;
9fb9cbb1 YK	490
9fb9cbb1	491	#ifdef CONFIG_SYSCTL
964ddaa1	492	cleanup_hooks:
964ddaa1	493	nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
32292a7f	494	#endif
9fb9cbb1 YK	495	cleanup_ipv4:
	496	nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
	497	cleanup_icmp:
	498	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
	499	cleanup_udp:
	500	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
	501	cleanup_tcp:
	502	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
	503	cleanup_sockopt:
	504	nf_unregister_sockopt(&so_getorigdst);
9fb9cbb1 YK	505	return ret;
	506	}
	507
65b4b4e8	508	static void __exit nf_conntrack_l3proto_ipv4_fini(void)
9fb9cbb1	509	{
32292a7f PM	510	synchronize_net();
	511	#ifdef CONFIG_SYSCTL
	512	unregister_sysctl_table(nf_ct_ipv4_sysctl_header);
	513	#endif
	514	nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
	515	nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
	516	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp);
	517	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4);
	518	nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4);
	519	nf_unregister_sockopt(&so_getorigdst);
9fb9cbb1 YK	520	}
9fb9cbb1 YK	521
65b4b4e8 AM	522	module_init(nf_conntrack_l3proto_ipv4_init);
65b4b4e8 AM	523	module_exit(nf_conntrack_l3proto_ipv4_fini);
9fb9cbb1	524
9fb9cbb1	525	EXPORT_SYMBOL(nf_ct_ipv4_gather_frags);